Yarn package winding method



March 21, 1967 T HAVE YARN PACKAGE WINDING METHOD Filed Aug. 31, 1964FIG.2

INVENTOR.

LAMBERTUS TEN HAVE United States Patent 3,310,248 YARN PACKAGE WINDINGMETHOD Lambertus Ten Have, Bennekom, Netherlands, assignor to AmericanEnka Corporation, Enka, N.C., a corporation of Delaware Filed Aug. 31,1964, Ser. No. 393,119 Claims priority, application Netherlands, Sept.4, 1963, 297,508 1 Claim. (Cl. 242-43) This invention relates to amethod of winding a yarn package and more particularly to a yarn packageof greater size having uniform porosity and uniformly drawn filaments.The invention also relates to a unique yarn package produced by thismethod.

Heretofore yarn packages having uniform porosity and uniform yarn layerthickness have been produced. However, such packages have beenrestricted in their size and are undesirable from an economy standpoint.Uniformity in package buildup is highly desirable, particularly in thefield of regenerated cellulose, in order to provide uniformaftertreatment of the packages as well as uniformity in denier strengthand affinity for dyeing.

It is known in the thread winding art to mount a thread guide closelyadjacent to a takeup spool onto which the thread is to be Wound and toreciprocate the guide longitudinally of the spool in order that thelayers of the thread may be evenly distributed along the surfacesthereof. Disadvantages exist in this particular manner of threadpackaging. In this type of apparatus, the thread is usually supplied atan angle substantially normal to the axis of the rotation of the spoolby the reciprocating guide, passing first through a stationary threadguide or roller which is located centrally of the spool length and at adistance therefrom. When the reciprocating guide reaches the endportions of the spool during its reversing movement, the thread beingfed from the stationary guide is displaced further and subjected to anincrease in tension. This increased tension not only produces anunevenly stretched yarn, but also produces tension pulses which resultin excess thread buildup on the end portions of the spool. Thischaracteristic is sometimes referred to as saddle effect and results innonuniform dyeing during liquid treatment and tends to cause the yarn tosluff off so that a self-supporting package cannot be produced.

Heretofore, these problems have been treated individually rather thancollectively by industry. As one means for maintaining uniform porosityin a wound package, Whitaker, in Patent No. 2,608,354, has provided anapparatus for producing a stroke displacement during the winding cycle.Jackson Patent No. 2,338,723 has provided a means for preventingslutling of the ends of the package consisting of an apparatus forproducing a stroke reduction during package winding. Additionally,Rutgers Patent No. 2,950,068 has dealt with saddle eifect by providingan apparatus for maintaining a constant thread travel distance betweenthe fixed and traveling thread guides to prevent uneven tensioning ofthe yarn during windup. Also, British Patent No. 674,615 providesapparatus for varying the velocity of traverse of the yarn guide toimprove package hardness.

In order that spinning machines can be still better utilized, a constanteffort is being made to increase the weight of the yarn contained inyarn packages. This may be done most simply by increasing the lengthand/or diameter of the yarn package. However, when the spool length andtraverse stroke of the reciprocating yarn guide are increased, thetension pulses in the winding thread become progressively stronger. As aresult, the yarn is stretched nonuniformily, unevenly built up on thespool Patented Mar. 21, .1967

package, and produces a package having uneven porosity. Experimentationhas indicated that by merely changing the traverse speed, the strokedisplacement, and the stroke reduction, it is not possible to obtain asatisfactory package buildup in yarn packages of this large size. Withthe unique method of the present invention, however, it has neverthelessbeen found possible to wind the yarn into packages having much higherweight and which can be aftertreated very satisfactorily.

It is an object of the present invention to provide a yarn package ofgreater capacity and not possessing the aforementioned disadvantages.

A primary object of the present invention is to provide a method ofproducing larger yarn packages of self-supporting, uniformly thicklayers having uniform porosity throughout the package. 7

An additional object of the invention is to provide a yarn packagehaving increased weight, uniform porosity, and uniform yarn layerthickness.

These and other objects of the invention will become more obvious fromthe following detailed description and accompanying drawings.

The improved yarn package of this invention having greater weightwithout sacrifice of uniformity is produced bya method in which thereciprocating yarn guide, during its traverse stroke, is provided withan initial high velocity over a small part of the stroke length,followed by a subsequent velocity decrease over an approximate equaldistance, and finally followed by a constant velocity level over theremainder of the stroke. Because of the relatively high initialvelocity, the duration of the reversing movement at each end of thetraverse stroke is reduced.

This quick traverse at the ends of the package results in decreasedtension pulses and uniform buildup of the package. By coupling thisquick reverse with the stroke reduction and stroke displacement, yarnpackages of greater length having a greater yarn capacity can beproduced without the heretofore mentioned loss in uniformity of thepackage.

The unique method involved can be more fully explained with reference tothe accompanying drawings in which:

FIGURE 1 is a velocity-distance diagram illustrating theoretical speedincreases and decreases during reciprocation of the thread guide alongthe yarn package; and

FIGURE 2 shows the course of the traversing stroke during windingoperation, specifically illustrating the stroke displacement and strokereduction.

FIGURE 1 depicts, by means of a velocity diagram, the speed of thetraverse thread guide during a complete cycle of forward and backwardmovement from an end portion of a rotating spool. The solid linerepresents the traverse motion or stroke from an initial end position tothe opposite end of the spool while the dotted line represents thereturn of the thread guide to its initial position. Distance Drepresents the total stroke length while distance A depicts the distanceof initial high velocity followed by a decrease in velocity overdistance B to a final constant velocity C throughout the stroke lengthwith velocity C being 30 to 60% lower than the constant velocity at thebeginning of the forward and backward strokes. In like manner, thereturn stroke, shown by the dashed lines,

. is initiated at the same speeds over correspondingly equivalentdistances A, B and C. Although the distances A, A and B, B arenecessarily small compared to the total stroke length, they may bevaried within certain limits. It stands to reason that the reversal ofdirection is not completely instantaneous but it will be as nearlyinstantaneous as modern construction will allow. A highly uniformpackage may be producedby maintaining distance A and A between 4 to 8%of the total stroke length D and the distance B and B between 6 to 10%of the stroke length D.

FIGURE 2 is a schematic presentation showing the course of thetraversing stroke during a complete package buildup. Distance G is theinitial stroke length laid on the surface of a collection spool, whiledistance H indicates the final stroke length on the outer surface of thepackage. The stroke displacement is indicated by distance E and thestroke reduction by distance F. Although the stroke displacement andstroke reduction may be varied, a highly uniform package has been foundto be produced by maintaining the stroke displacement and the strokereduction at less than 10% and 20% of the length of the main stroke,respectively.

The method practiced in this invention will become more apparent fromthe following specific example. A package of increased weight and yarncapacity was pre pared from regenerated cellulose in which thecollection spool length was increased from 180 to 255 mm. The packagewas wound using the traverse speed of 320 mm. per second, which resultedin unacceptable tension pulses in the yarn and consequent saddle effectat the ends of the package. By reducing the traverse speed to 255 mm.per second, the tension pulses were eliminated; however, it was notpossible to obtain a self-supporting package with uniform thickness ofthe yarn layers and a uniform porosity by experimentally varying thestroke displacement and stroke reduction at this traverse speed.

A spool of the same length was then wound using the unique traversingmethod of this invention. At the beginning of every stroke, velocity ofthe thread guide was set to 450 mm. per second for a distance of mm. anddecreased during the following mm. of travel to a constant speed of 255mm. per second over the rest of the stroke length. During the winding ofthe package, the stroke displacement was set to 15 mm. and the strokereduction to 38 mm. The main stroke of the traverse motion was set to 31cycles per minute. The yarn package thus produced contained double theyarn weight of previously wound packages having the same uniformporosity, uniform yarn layer thickness, and equivalent self-supportingcharacteristics.

Inasmuch as other modifications will become apparent to those familiarwith this art, it is intended that the scope of this invention belimited only to the extent of the following claim.

What is claimed is:

A method of winding a heavy yarn package on a rotating spool by the useof a traversing yarn guide incorporating a stroke reduction and a strokedisplacement therein, said yarn guide laying successive layers of yarnon the spool by means of forward and backward strokes along the lengthof the spool, comprising the steps of:

(a) maintaining an initial high velocity of the thread guide at thebeginning of each stroke at each end of the collection spool for adistance 4 to 8% of the stroke length;

(13) decreasing the velocity of the guide for a distance of 6 to 10% ofthe stroke length;

(c) maintaining a decreased constant velocity of the thread guide forthe remainder of the stroke length 30 to lower than the constantvelocity at the beginning of the forward and backward stroke; and

(d) maintaining the stroke displacement and the stroke reduction lessthan 10% and 20% of the initial stroke length, respectively.

References Cited by the Examiner UNITED STATES PATENTS STANLEY N.GILREATH, Primary Examiner.

